He was Transformed

Harry's face paled.

"G-girl?"

"Ah well, not entirely." She amended, gesturing towards his crotch.

"Heritage potions are usually only given to pregnant women, not almost fully grown boys. You know how purebloods are about their offspring, got to have a male heir to inherit the title, bla bla bla." She made a yapping motion with her hand, signifying what she thought about that.

"Of course, not all families want a boy, some are hoping for a daughter to marry to rich families and advance their own name and influence." Her face took a distinctive look of dislike at that.

The pieces of the puzzle suddenly formed a daunting picture in Harry's mind.

"You made me drink one?!" He screamed.

Her answering grin already told him all he needed to know, but she decided to elaborate. “Yes sweetie, a modified one, although it wasn't quite as effective as having someone take it while the child is still in the womb, it still gave you some very striking features." She cooed, leaning over and brushing her hand over his smooth cheek.

Harry felt nauseous, barely hearing her as she continued.

"Of course with all the work the potion had to do it had to get energy from somewhere else in your body, changing a teenager is quite different to changing an unborn child. Your muscles and magic were a great source for that." She smiled, her hand running over his girly arms.

"They will rescue me." He muttered, not certain if he even believed it himself.

"Oh darling," she murmured, wiping away a stray tear from his cheek, "I have had you for weeks, they have no idea where you could be."

Her words however hammered home the truth. He was completely and utterly at her mercy. Which is why he was very surprised when she flicked her wand, removing the straps that held her down. It took him considerable effort but he managed to sit up on the edge of the makeshift bed with a soft groan.

"No permanent damage!" Bellatrix giggled, clapping her hands at his performance.

Now that he looked at her he realized she had holstered her wand, his frame slowly tensing as he sensed an opportunity. Just as she was about to say something he jumped off the bed, his muscles groaning in protest as he attempted to tackle her to the floor where he could overpower the woman.

He never even made it that far, Bellatrix calmly caught his arm and sidestepped his feeble charge, twisting the arm behind his back. He gasped in pain, but even more in realization of just how weak he was now. His strength was pitiful, even if he was fully rested and limber he doubted she'd even notice his punch.

"Bad girl!" Bellatrix scolded, sitting back in her chair and folding him over her lap. She barely even noticed his attempts to struggle and Harry's eyes widened when he suddenly felt a harsh slap to his buttocks. He inhaled sharply, a gasp of pain slipping past his lips. She was spanking him. He couldn't believe it.

Slap! Another sharp slap to his butt cheek shredded any disbelief he might have left, he groaned and wriggled, trying to escape her hand as she rained down slaps on his ass. He couldn't understand why it hurt so much, his pain tolerance had always been quite considerable, yet the simple spanking hurt something fierce.

"Please!" He gasped, tensing his muscles to try to alleviate the pain of her strong solid hand tanning his hide.

Bellatrix stopped for a second, meeting his green pleading eyes. “Please?" She asked. "Please what? You behaved like a bad girl and you deserve your punishment."

"I'm sorry!" He moaned, panting heavily as it felt like his skin was on fire.

"Oh I bet you are sweetie, I've cast a Supersensory Charm on you, not only does it make more sensitive to all stimulation, it also does quite interesting things to any pain caused to you."

Harry suddenly understood why he had been so sensitive to her touch earlier. He watched her raise her hand above his buttocks again and closed his eyes, tensing for the inevitable pain.

"But," Bellatrix began, making his eyes snap open, "considering it's your first time being a bad girl I might let you go with this light punishment, if admit to it and promise to never do it again."

"I'll never do it again! I promise!" Harry gasped, the lie slipping past his lips smoothly, anything to avoid the pain.

"Aaaand?" She inquired.

"I'm sorry for being bad?" Bellatrix raised her hand again and Harry understood what she wanted.

"I'm sorry for being a bad girl," he stuttered out, feeling immensely humiliated.

Bellatrix smiled happily and her previously intimidating hand instead gently caressed his burning butt cheeks, making him shiver at the strange sensation. He exhaled loudly in relief, trying to get up from her lap but she firmly held him down.

"Not yet my pretty, you have some things to learn,” she said.